Exploring how areas of the brain communicate with each other is the focus of a long-standing research collaboration between Carnegie Mellon University, Albert Einstein College of Medicine and Champalimaud Research.
The intercontinental team simultaneously records populations of neurons in several brain areas of the visual system and uses new statistical methods to observe patterns of neural activity transmitted between areas. Their latest findings reveal that feedforward and feedforward signaling involve different patterns of neural activity, providing new understanding of how the brain processes visual information.
A myriad of brain functions, such as seeing, hearing, and making decisions, require multiple brain areas to communicate with each other. Researchers have previously studied pairs of neurons or an aggregate measure of neural activity in multiple domains to assess how information is captured, processed, and then used in daily life. Few groups have studied, in such detail, populations of neurons together to see what kind of patterns of activity are communicated across brain areas.
“The idea of this study was to study how information flows in two areas of the visual cortex, V1 and V2”, explains João D. Semedo, first author of the work published in Nature Communication and former doctorate in electrical and computer engineering. raised. “We had good reason to believe that the zones were communicating with each other, based on anatomy, but tracking the flow of signals between the zones turned out to be very difficult.”
Thanks to the pioneering technology of Dr. Kohn’s laboratory, we were able to record several brain areas at the same time and, in each of these brain areas, record many neurons. It is the activity of a group of neurons together that tells us what is specifically going on. Next, we creatively applied statistical methods to extract signals that had not been extracted before..”
João D. Semedo, Study First Author, College of Engineering, Carnegie Mellon University
In their analysis, the group identified directed interactions between brain areas and confirmed that patterns of activity in feedforward interactions (from V1 to V2) differed from patterns of activity in feedback interactions (from V2 to V1). Weekly meetings and a close-knit, team-oriented approach kept people connected on all aspects of the job and contributed to their success.
“Understanding what is communicated from one area of the brain to another is difficult to disentangle because signals flow in all directions, all the time,” says Adam Kohn, professor of neuroscience at Albert Einstein College of Medicine. “What excites me most about this work is the prospects it opens up for the future. If we can identify the patterns of activity involved in different signaling directions, it will be a big step forward in understanding of brain function.”
More broadly, these methods could be applied to study communication flow in other areas of the brain, outside of the visual system.
“Studies like these increase our basic scientific understanding of brain function,” says Byron Yu, professor of biomedical engineering and electrical and computer engineering. “Many brain disorders involve a breakdown in communication between brain areas. This pioneering work could lead to new treatments for these disorders, and even help us develop new methods to promote brain development and ways to learn. .”
Samedo, J.D. et al. (2022) Feedforward and feedback interactions between visual cortical areas use different patterns of population activity. Nature Communication. doi.org/10.1038/s41467-022-28552-w